1. Field of Invention
The present invention relates to a driving support system which displays information for supporting the operation of a vehicle in conjunction with an image showing a view toward the direction in which the vehicle is traveling. Further, the present invention relates to a steering angle detection device for detecting a steering angle of the vehicle on the basis of driving support information.
2. Description of Related Art
Sufficient ascertaining of the surroundings of a vehicle is necessary for accomplishing safe driving. The driver ascertains the surroundings of his vehicle primarily by means of the sense of sight. Since the driver has to look outside the vehicle from the driver""s seat in the vehicle""s cabin, the driver""s field of view is obstructed by the vehicle body. In order to ensure the driver""s field of view, a proposal has hitherto been made for supporting a driver""s operation by means of displaying an image of the outside of the vehicle on a display panel located in the vicinity of the driver""s seat, through use of an image pick-up device, such as a video camera, attached to the vehicle.
The present inventor has hitherto made various proposals for supporting such an image-based driver""s operation, as described in, for example, Japanese Patent Application Laid-Open Nos. 288255/1998, 301207/1998, 301208/1998, 353425/1998, 353426/1998, and 179718/1999.
Vehicle driving support is effective particularly when an attempt is made to park a vehicle. As a conventional art technique for supporting a driver""s parking operation, for example, Japanese Patent Application Laid-Open No. 14700/1989 describes a technique of displaying, on a screen, an image concerning a rearward or rear oblique when the vehicle is rolling backward and a predicted path of the vehicle. According to the prior technique, an image of predicted path based on a steering angle of the vehicle is displayed with and is superimposed on a rearview image. Accordingly, it is predicted that the driver can simultaneously ascertain a steering angle and the rearward safety of the vehicle. There is also described the idea of displaying the contour of a vehicle so as to be superimposed on the vehicle""s predicted path, thereby facilitating the driver""s intuitive ascertainment of distance. Further, Japanese Patent Application Laid-Open No. 44799/1995 describes a conventional art technique of detecting the length of a parking space through use of various sensors and assisting a driver""s operation by means of informing the driver of whether or not the vehicle can be parked in the parking space in a case where the driver attempts to park his vehicle between vehicles arranged end to end or put his vehicle into a garage. The patent application also describes that the amount of steering operation is computed from data pertaining to the position of a parking space and data pertaining to the characteristics of a vehicle, to thereby provide a display for driving support purpose or perform an automatic control operation.
Conventional art techniques for supporting driving operations by means of capturing an image of surroundings of a vehicle are described in, for example, Japanese Utility Model Application Laid-Open No. 150044/1982 and Japanese Patent Application Laid-Open Nos. 239400/1992, 143894/1993, 255423/1994, 192199/1995, 257482/1998, and 283592/1998.
Japanese Utility Model Application Laid-Open No. 150044/1982 describes the technique of supporting driving operation by means of switching a screen of a display from a normal screen image for indicating selected information under normal operation to an anomalous display screen for indicating information about an anomalous state. Japanese Patent Application Laid-Open No. 239400/1992 describes the technique of capturing images of surroundings in desired locations through use of a camera which is attached to the vehicle""s ceiling by way of a rotary pan head and which is rotatable through 360xc2x0 in a horizontal direction, subjecting the thus-captured images to image processing so as to make them easily readable for the driver, and displaying the thus-processed images on a display unit simultaneously or in a split screen, as required. Japanese Patent Application Laid-Open No. 143894/1993 describes the technique of capturing images of a vehicle in a left forward direction, a forward direction, and a right forward direction of the vehicle through use of three cameras, displaying the thus-displayed images in a three-way split screen, and changing the proportion of the display area of the leftward image to the display area of the rightward image within the split display in accordance with a steering angle. Japanese Patent Application Laid-Open No. 255423/1994 describes the technique of displaying an image captured by a camera together with range scales based on a distance measured by a range sensor, and displaying an image concerning surroundings of obstacles in a scaled-up manner, in a size so as to match the distance, thereby assisting driving operation. Japanese Patent Application Laid-Open No. 192199/1995 describes the technique of three-dimensionally analyzing an obstacle on the basis of a stereoscopic image, computing the distance between an extension of the side of a vehicle and the obstacle, computing a clearance between the vehicle and the obstacle, and displaying the thus-computed clearance when the vehicle passes through a narrow path. Japanese Patent Application Laid-Open No. 257482/1998 describes the technique of displaying an image in the form of a seamless single frame by means of merging a rearview, a left-side view, and a right-side view of the vehicle into a single image. Japanese Patent Application Laid-Open No. 283592/1998 describes the technique of three-dimensionally analyzing an image captured by a camera, determining the chance of contact arising between a vehicle and an obstacle, informing a driver of the result of determination, and displaying the spatial relationship between the vehicle and the obstacle.
Even when driving support is effected on the basis of an image, the driver must determine circumstances directly on the basis of his vision, and a display for assisting driving operation must be utilized for only auxiliary purpose. A limitation is imposed on the size of display means situated in the vicinity of a driver""s seat. Display of a predicted path of a vehicle together with an image is preferable for effectively assisting driving operation. A predicted path of the vehicle corresponds to informationxe2x80x94which the driver can never gain by means of looking directly at surroundingsxe2x80x94and is very useful.
A predicted path of the vehicle displayed in an image captured by a camera or the like should be changed by an angle of the camera mounted on a vehicle body, a steering angle of the vehicle, the width of the vehicle body, and a wheelbase. A path cannot be accurately predicted without matching data pertaining to these items with an actual vehicle, and hence effective driving support cannot be effected. In terms of productivity of manufactured products, a driving support system is desirably mountable on vehicles of many types. Preferably, required data can be readily input in accordance with the specifications of an individual vehicle. Further, under the present circumstances, a vehicle is not usually provided with a sensor for detecting the steering angle of a vehicle, which is required for predicting a path. Therefore, simplest detection of a steering angle is desirable.
An object of the present invention is to provide a vehicle driving support system and a steering angle detection device, which easily compensates for a difference in specifications of a vehicle on which the system is to be mounted, and which enables highly-accurate support.
Accordingly, the present invention provides a vehicle driving support system which captures an image of the surroundings of a vehicle through use of a camera and displays on display means driving support information along with the captured image, the system comprising:
a steering angle sensor for detecting a steering angle of a vehicle;
travel prediction means which predicts a travel path of the vehicle on the basis of a steering angle detected by the steering angle sensor and computes the thus-predicted travel path as a predicted travel curve;
memory in which, in connection with specifications of any of a plurality of vehicles, there are stored beforehand data pertaining to the space which would be occupied when a vehicle travels along a predicted travel curve computed by the travel prediction means;
selection operation means by way of which an input operation is performed for selecting data to be stored in the memory, in accordance with specifications of a vehicle; and
control means which computes, as driving support information, a path pertaining to a space by which the vehicle is predicted to pass in accordance with travel of the vehicle on the basis of the predicted travel curve predicted by the travel prediction means and through use of the data selected by means of an input operation of the selection operation means, and which causes the display means to display the computed path.
According to the present invention, the vehicle driving support system for displaying driving support information along with an image of the surroundings of a vehicle comprises a camera, display means, a steering angle sensor, travel prediction means, memory, selection operation means, and control means. The steering angle sensor detects a steering angle of the vehicle. The travel prediction means predicts the travel path of the vehicle on the basis of the steering angle detected by the steering angle sensor and computes the thus-predicted travel path as a predicted travel curve. In memory, in connection with specifications of any of a plurality of vehicles there are stored beforehand data pertaining to the space which would be occupied when a vehicle travels along the predicted travel curve computed by the travel prediction means. By way of selection operation means, an input operation is performed for selecting data to be stored in the memory, in accordance with specifications of a vehicle.
On the basis of the predicted travel curve predicted by the travel prediction means, control means computes, as driving support information, a path pertaining to a space by which the vehicle is predicted to pass in accordance with travel of the vehicle, through use of the data selected by means of an input operation of the selection operation means. The thus-computed path is displayed on the display means. When the path is displayed on the display means along with an image, the predicted path is displayed so as to match the video to be displayed on the display means. A highly-accurate predicted path is displayed, to thereby provide easily-understandable driving support. Data pertaining to specifications of several types of vehicles are stored in memory beforehand. Consequently, a highly-accurate predicted path can be effected by means of selection of optimal data through use of the selection operation means, which is easier than selection by means of direct input of individual data sets.
Preferably, information concerning one or more of a wheeltread of the vehicle, a wheelbase of the vehicle, the amount of kingpin offset, and a height at which the camera is to be mounted is stored in the memory as the data.
According to the present invention, data pertaining to one or more of a wheeltread of the vehicle, a wheelbase of the vehicle, the amount of kingpin offset, and a height at which the camera is to be mounted are stored in the memory. The distance between the treads of tires disposed at respective ends of an axle shaft can be determined from the wheeltread. Further, the distance between the center lines of the front and rear wheels can be determined from the wheelbase. These distances facilitate computation and prediction of a path on the basis of the steering angle. Since the height at which a camera is to be mounted is also given as data, the manner in which the predicted travel curve computed within the ground surface appears within the image captured by the camera can be readily computed from the relationship between the state of the ground surface captured by the camera and the shooting direction of the camera. Since required data can be selected from the data stored in the memory, the required data can be acquired by means of the driver performing only a selecting operation. Effective driving support can be effected without involvement of efforts for entering data to compensate for a difference in specifications between the vehicles.
Since the data pertaining to a vehicle comprise one or more of a wheeltread, a wheelbase, and the amount of kingpin offset, a minor difference of specifications of a vehicle can be compensated for. Hence, the data stored in the memory can be made sharable between vehicles of various types. There can be prevented exhaustion of available memory space, which would otherwise be caused by storage of duplicate data.
The present invention also provides a vehicle driving support system which captures an image of the surroundings of a vehicle through use of a camera and displays on display means driving support information along with the captured image, the system comprising:
a steering angle sensor for detecting a steering angle of a vehicle;
travel prediction means which predicts a travel path of the vehicle on the basis of a steering angle detected by the steering angle sensor and computes the thus-predicted travel path as a predicted travel curve;
memory in which there are stored beforehand data pertaining to the space which would be occupied when a vehicle travels along a predicted travel curve computed by the travel prediction means; and
control means which computes, as driving support information, a path pertaining to a space by which the vehicle is predicted to pass in accordance with travel of the vehicle on the basis of the predicted travel curve predicted by the travel prediction means and through use of the data selected by means of an input operation of the selection operation means, and which causes the display means to display the computed path,
wherein the control means causes the display means to display the path and does not cause the display means to display the path when the speed of the vehicle becomes greater than a predetermined speed.
According to the present invention, since a predicted path is displayed on display means, a path which changes in accordance with a steering angle can be displayed in an easily-readable manner. Further, when the speed of the vehicle becomes greater than a predetermined speed, the path is not displayed. Thus, the driver can concentrate his use of the sense of sight on only driving.
The present invention also provides a vehicle driving support system which captures an image of the surroundings of a vehicle through use of a camera and displays on display means driving support information along with the captured image, the system comprising:
a steering angle sensor for detecting a steering angle of a vehicle;
travel prediction means which predicts a travel path of the vehicle on the basis of a steering angle detected by the steering angle sensor and computes the thus-predicted travel path as a predicted travel curve;
memory in which there are stored beforehand data pertaining to the space which would be occupied when a vehicle travels along a predicted travel curve computed by the travel prediction means; and
control means which computes, as driving support information, a path pertaining to a space by which the vehicle is predicted to pass in accordance with travel of the vehicle on the basis of the predicted travel curve predicted by the travel prediction means and through use of the data selected by means of an input operation of the selection operation means, and which causes the display means to display the computed path,
wherein the control means causes the display means to display guidelines representing extensions of sides of the vehicle and does not cause the display means to display the guidelines when the speed of the vehicle becomes greater than a predetermined speed.
According to the present invention, guidelines are displayed for supporting driving of a vehicle. When the speed of the vehicle exceeds a predetermined speed, switching is made to prevent display of guidelines. When the vehicle speed exceeds a predetermined speed, the driver can easily ascertain the path without display of guidelines.
Preferably, the control means makes the predetermined speed match a speed limit imposed on vehicle-mounted equipment.
According to the present invention, the speed at or above which guidelines or a predicted path is not displayed is determined so as to match a speed limit imposed on on-vehicle equipment. Consequently, effective driving support can be effected in association with the state of use of the on-vehicle equipment.
The present invention also provides a vehicle driving support system which captures an image of the surroundings of a vehicle through use of a camera and displays on display means driving support information along with the captured image, the system comprising:
a steering angle sensor for detecting a steering angle of a vehicle;
travel prediction means which predicts a travel path of the vehicle on the basis of a steering angle detected by the steering angle sensor and computes the thus-predicted travel path as a predicted travel curve;
memory in which there are stored beforehand data pertaining to the space which would be occupied when a vehicle travels along a predicted travel curve computed by the travel prediction means; and
control means which computes, as driving support information, a path pertaining to a space by which the vehicle is predicted to pass in accordance with travel of the vehicle on the basis of the predicted travel curve predicted by the travel prediction means and through use of the data selected by means of an input operation of the selection operation means, and which causes the display means to display the computed path,
wherein the control means changes the length or color of a path to be displayed, in accordance with the speed of the vehicle.
According to the present invention, the length or color of a predicted path to be displayed is changed whether the vehicle drives at a speed slower than a predetermined speed or is stationary. Therefore, driving support can be effected so as to match a vehicle speed while displaying whether the vehicle is driving or stationary.
Preferably, the control means changes the length or color of the path stepwise in accordance with the vehicle speed.
According to the present invention, the length or color of a predicted path is changed stepwise in accordance with the speed of the vehicle. Therefore, safety can be improved in accordance with the speed of the vehicle.
The present invention also provides a vehicle driving support system which captures an image of the surroundings of a vehicle through use of a camera and displays on display means driving support information along with the captured image, the system comprising:
a steering angle sensor for detecting a steering angle of a vehicle;
travel prediction means which predicts a travel path of the vehicle on the basis of a steering angle detected by the steering angle sensor and computes the thus-predicted travel path as a predicted travel curve;
memory in which there are stored beforehand data pertaining to the space which would be occupied when a vehicle travels along a predicted travel curve computed by the travel prediction means;
obstacle detection means for detecting an obstacle which is present in the travel direction of the vehicle; and
control means which computes, as driving support information, a path pertaining to a space by which the vehicle is predicted to pass in accordance with travel of the vehicle on the basis of the predicted travel curve predicted by the travel prediction means and through use of the data selected by means of an input operation of the selection operation means, and which causes the display means to display the computed path,
wherein the control means changes the length or color of the path, in accordance with the result of detection performed by the obstacle detection means.
According to the present invention, since the length or color of the path is changed in accordance with the result of obstacle detection performed by the obstacle detection means, the driver can readily ascertain the presence of an obstacle and acquire information about the distance to the obstacle. Thus, effective driving support can be provided for avoiding the obstacle.
Preferably, the obstacle detection means outputs one of predetermined detection signal of several stages in accordance with the distance to the detected obstacle, and the control means changes the length or color of the path in stages in accordance with a detection signal output from the obstacle detection means.
According to the present invention, since the length or color of a predicted path can be changed in accordance with the distance to an obstacle, driving support pertaining to an approach to an obstacle can be provided in an easily-understandable manner.
The present invention also provides a vehicle steering angle detector for detecting a steering angle of a vehicle from an exposed portion of a steering shaft which rotates in response to the actuation of a steering wheel, the exposed portion being located within a vehicle body, the detector comprising:
a steering angle sensor which detects the amount of angular displacement of the steering shaft at the exposed portion of the steering shaft; and
a bracket whose base end is secured to the vehicle body in the vicinity of the exposed portion of the steering shaft, by means of utilization of screws to be used for fixing bearings of the steering shaft to the vehicle body, and which has a geometry satisfying requirements for the vicinity of the steering shaft of the vehicle so that the steering angle sensor can be attached to the front end of the bracket.
According to the present invention, the steering angle of a vehicle can be detected through use of an exposed portion of a steering shaft which rotates in response to actuation of a steering wheel, the exposed portion being located within a vehicle body. A steering angle sensor is attached to the vicinity of the exposed portion of the steering shaft through use of a bracket and by means of utilization of screws to be used for mounting bearings of the steering shaft to the vehicle body. The bracket has a geometry satisfying requirements for the vicinity of the steering shaft of the vehicle such that the base end of the bracket is mounted on the vehicle body and such that the steering angle sensor is attached to the front end of the bracket. Accordingly, the rotation of the steering shaft is accurately detected without fail, and the steering angle to be used for predicting the path of a vehicle can be readily detected.
Preferably, the vehicle steering angle detector further comprises a splittable shaft gear to be fitted around the exposed portion of the steering shaft; and a detection gear which is rotatably supported by the bracket and meshes with the shaft gear and whose rotation is detected by the steering angle sensor.
According to the present invention, a splittable shaft gear is fitted around the exposed portion of the steering shaft, and a detection gear which meshes with the shaft gear is rotatably supported. The rotation of the detection gear is detected by the steering angle sensor, and hence the rotation of the steering shaft can be detected without fail. The thus-detected rotation can be utilized for predicting the path of the vehicle.